The consumer acceptance of meat, e.g. beef, pork and polutry, depends, to a large measure, on the tenderness of the meat after cooking. When the meat is tough and fibrous, consumer acceptance is quite low. Meat prepared for home consumption and sold in local groceries and butcheries is normally of the more tender grades, e.g. choice or prime in the case of beef. To obtain those more tender grades, the animals or fowl must be carefully selected and in the case of beef, lot feeding of the beef is required in order to develop in the muscle tissue the desired amount of tenderness, including increases fat content, referred to a marbling. However, such lot feeding considerably increases the cost of the meat, and for this reason considerable effort has been expended in the art to provide methods for tenderizing less tender grades of meat, e.g. cutter, canner, utility or commercial grades in the case of beef. In addition, the more tender grades, e.g. choice grade in the case of beef, sometimes still do not have the degree of tenderness desired and the art has sought methods for improving the tenderness of these more tender grades.
Generally speaking, the efforts in the art for improving the tenderness of meat have taken three different approaches, i.e. aging, mechanical and chemical tenderization, although these approaches are not mutually exclusive. Aging the slaughtered meat is a traditional approach, but this requires cold storage of the meat for substantial lengths of time and considerably increases the cost of the meat. In addition, aging necessarily entails some loss of meat due to the aging process.
Mechanical tenderization of the meat is achieved by passing the meat through mechanical tenderizers. However, such mechanical tenderizers may substantially change the texture and appearance of the meat and, accordingly, render the meat less desirable, except in regard to certain cooking applications. Typical of such mechanical tenderization is the conventional "cubed" steak. More severe mechanical tenderization results in "ground" meat, and this extreme mechanical tenderization severely limits the mode of cooking the meat. Thus, neither aging nor mechanical tenderization is fully satisfactory.
One approach of chemical tenderization is that of enzyme tenderization. In this method, enzyme solutions are placed in and on the meat, and during storage of the meat at above freezing temperatures, the enzymatic action causes degradation of protein and a tenderization of the meat. However, with enzyme tenderization it is critical that the enzyme solution be relatively uniformly dispersed on and in the meat, since non-uniform dispersement will result in non-uniform tenderization and can result in over tenderization. Thus, if a large amount of the enzyme solution is localized in the meat, that portion will become exceedingly tender that even of a "mushy" consistency, while in other areas of the meat where the amount of enzyme solution is much lower, the meat may remain relatively tough. Thus, enzyme tenderization not only requires some aging time, but is difficult to control from the uniform tenderness point of view.
Another method of chemical tenderization is that of tenderization with phosphate solutions. These solutions will more quickly cause tenderization of the meat and long dwell times are not required, e.g. times of 4 to 8 days have been suggested (see U.S. Pat. No. 3,207,608). However, similar to enzyme solutions, the uniformity of tenderization depends upon the uniformity of dispersing the phosphate solutions in the meat, although the action thereof does not cause the excessive over tenderization, as do enzymes. However, the phosphate tenderization requires substantial amounts of water to be associated therewith, as opposed to the amount of water normally used in enzyme solutions. Typically, the amount of enzyme solution placed in the meat is only about 3%, whereas the amount of phosphate solution placed in the meat is ideally about 10%, i.e. the use of phosphates requires about three times as much solution to be placed in the meat. As a result, it has been difficult for the art to place that higher amount of tenderizer solution in the meat and, hence, achieve adequate tenderization with phosphate solutions.
In this latter regard, cut portions of meat have been allowed to dwell in phosphate solutions for considerable lengths of time. However, this process is exceedingly slow and not economical from a commercial point of view. In addition, it is difficult for the phosphates to permeate the entire cut portion of meat and unequal tenderization results.
More recently, the art has porposed combinations of mechanical and chemical tenderization, i.e. with enzymes and phosphates. For example, in U.S. Pat. No. 3,971,854, it is proposed that meat (in this case "choice" subprimal cuts) be mechanically tenderized by passing the meat through a multiple blade (or pin) type tenderizer where reciprocating blades completely penetrate the meat to tenderize it. Thereafter, an aqueous solution of phosphate is pumped into the meat by way of stainless steel needles and high pressure. However, pumping of phosphate solutions into the meat, either with or without mechanical tenderization is not entirely satisfactory, since a uniform dispersement of the phosphate solution in the meat is not achieved by way of a practical number of needles piercing the meat. Some success has been experienced by pumping the phosphate solution through the arterial network of whole hams, but this process is not applicable to cut serving portions of meat. In addition, trimmings from the subprimal cuts, when cutting into serving portions, cannot be used to produce pure beef or unflavored beef products. About 15%-35% of the usual subprimal cut is trimmings when cutting serving size steaks.
Canadian Pat. No. 792,201 suggests treating meat with either a liquid or dry phosphate composition, wrapping the treated meat in plastic film and allowing the meat to age for a period time. While this will provide an opportunity for the phosphates to penetrate the meat and effect some tenderization, the time period required for meaningful penetration of the phosphate is too long for commercial operation. Also see U.S. Pat. No. 3,625,708.
In U.S. Pat. No. 3,149,554 there is disclosed a tenderizer which has a pair of knife rolls which are mounted on axles for rotation and which are adapted to receive thereinbetween conveyed meat cuts. Each axle has a plurality of cuber knives with discrete relatively flat-faced cutting surfaces for placing cubing cuts in the meat passing between the rotating knives. Tenderizer solution is flooded on the meat as it passes between the knives to impregnate the meat with tenderizer solution. However, it was found that the foregoing arrangement, in practice, is difficult to control in terms of the amount of tenderizer impregnated into the meat cuts. In addition, the cuber knives were found to unduly destroy the integrity of the meat cuts, even with minimal use thereof, such that the tenderized meat had a texture and appearance similar to "cubed" steak, as opposed to the desired texture and appearance of a fresh steak.
U.S. Pat. No. 3,719,504 suggests that the foregoing difficulties may be avoided by the use of the combination of spray nozzles for spraying the tenderizer solution and the use of a plurality of elongated, pointed pins for perforating the meat, as opposed to the "cuber" knives. In this process the plurality of pins penetrate the meat from one side and immediately thereafter the apertured meat is sprayed with a tenderizing solution (unidentified) so that the solution can be received in the apertures prior to the apertures being closed by natural relaxation of the tissue around the apertures. However, in this case, the pins (of a Bettcher reciprocating tenderizer type) are quite narrow and the resulting apertures pick-up only about 3% of tenderizing solution, i.e. suitable only for enzyme solutions. Additionally, even that process causes difficulties, in that the apertures formed by the pins, while effective in receiving and retaining tenderizing solution, create considerable concentrations of tenderizing solution in the perforated areas and result in what is referred to in the art as "hot spots", i.e. spots where the meat becomes mushy and unpalatable.
To avoid the foregoing further developed problem, it has been further proposed in that process that, subsequent to penetrating the meat with the reciprocating pins and spraying, the meat be further cut with the rotataing cubing knives but only to the extent to further distribute the tenderizing solution and avoid the "hot spots". While this arrangement works reasonably well for tenderizing solutions which are to be contained in the meat in an amount of only about 3% or so, i.e. enzyme tenderizing solutions, difficulties have been experienced in containing greater amounts of tenderizing solutions in the meat, i.e. tenderizing solutions which depend upon phosphates for tenderization. Thus, when sufficient penetrations of pins are used to accommodate the higher amounts of tenderizing solutions, i.e. above about 5% or more, the many pin penetrations tend to undesirably mechanically disintegrate the meat, and produce an unpalatable soft texture, tending to be in the nature of "cubed" steak.
As can therefore be appreciated, the art has experienced considerable difficulty in reaching a satisfactory balance between mechanical disruption of the meat fiber for infusing the meat with tenderizing solution, and producing a texture of the tenderized meat which is acceptable to the consuming public. This has been a particular problem with less tender grades of meat, i.e. canner, utility, commercial and cutter grades. It would therefore be of considerable advantage to the art to provide a method for tenderizing meats while at the same time retaining a desirable texture of the tenderized meat. It would further be of advantage to the art to provide such processes wherein the tenderization may take place as an essentially continuous process, all the way through freezing, and where no lag period is required for action of a tenderizing solution.